Well, I've gone through quite a few basses, and I'm still trying to settle on my fretted bass. I find that my quiver depends on what music I'm playing...although my Lightwave has changed my opinion somewhat. I've made the leap from 4 to 5, so here's what I use:
5-string Zon Lightwave fretless. Don't need another fretless. Hell, I rarely play a fretted bass even. I fell in love with this bass at the store, but what really blew my mind was the first recording/group session. The first rehearsal with this bass (fusion trio), we also recorded direct to disk (DI out of my iAmp 600 head). Unbelievable tone. Sits perfect in the mix. Both the guitarist and drummer said "that sounds awesome". I did a few tunes with my Lakland 55-94 deluxe and it *paled* in comparison.
5-string fretted. I still haven't found "the one" yet. I've gone through a few Sadowskys's, and am currently fiddling with a Zon, Lakland, and Ken Lawrence. The 34" v. 35" scale thing is an issue with me, so I don't know how this will end up. I play fretless about 90% of the time, but you gotta have a fretted bass for some tunes.
Other than that, more basses are just a luxury for me. But then again, I'm not trying to capture a certain tone or vibe...I'm just trying to get something that I think sounds good.